288 EXTINCT MONSTERS 



Darwin obtained an almost entire skeleton of one of these. It 

 was as large as a polar bear. Speaking of his discovery, he says, 

 " The beds containing the fossil skeletons consist of stratified 

 gravel and reddish mud ; a proof that the elevation of the land 

 has been inconsiderable since the great quadrupeds wandered 

 over the surrounding plains, and the external features of the 

 country were then very nearly the same as now. The number of 

 the remains of these quadrupeds embedded in the vast estuary 

 deposits which form the Pampas and cover the granitic rocks 

 of Banda Oriental must be extraordinarily great. I believe a 

 straight line drawn in any direction through the country would 

 cut through some skeleton or bones. As far as I am aware, not 

 one of these animals perished, as was formally supposed, in the 

 marshes or muddy river-beds of the present land, but their bones 

 have been exposed by the streams intersecting the subaqueous 

 deposit in which they were originally embedded. We may con- 

 clude that the whole area of the Pampas is one wide sepulchre of 

 these extinct gigantic quadrupeds." l 



The genus Scelidotherium comprises a number of species and 

 presents characters more or less intermediate between Mega- 

 therium and some other genera. The skull is low and elongated, 

 and shows an approach to that of the modern ant-eater. The 

 feet also are different from those of Megatherium (see Fig. 109). 



These monster sloths inhabited South America during the 

 latest geological period, known as the Pleistocene. During part 

 of that time North America, as well as Northern Europe and 

 Asia, were invaded by a great ice-sheet, and an arctic climate 

 prevailed. It is therefore very probable that while the mammoth 

 and the mastodon were roaming over North America, giant sloths 

 and armadillos were monarchs of the southern continent. What 



1 Journal of Researches. 



